An igniter including a switching element such as an IGBT and a control circuit section configured to control operation of the switching element has been known as an igniter for igniting an ignition plug of an internal-combustion engine (refer to Patent Literature 1 below). The switching element is connected to a primary winding of an ignition coil. Moreover, a secondary winding of the ignition coil is connected to the ignition plug. The igniter is configured such that the control circuit section performs on/off operation of the switching element to generate high voltage at the secondary winding and ignite the ignition plug.
A protection element such as a protective resistor or a protection Zener diode is connected to the control circuit section. The protective resistor is provided on a current path between a DC power source and the control circuit section. The protective resistor is configured to absorb any high-energy high-voltage surge caused upon occurrence of so-called load dump, thereby protecting the control circuit section from such a surge. Moreover, the protection Zener diode is connected in parallel with the control circuit section, and is configured to keep a voltage applied from the DC power source to the control circuit section at a constant value. With this configuration, application of high voltage to the control circuit section is avoided, and the control circuit section is protected. These protection elements such as the protective resistor and the protection Zener diode are elements with a relatively high thermal rating, and therefore, are formed separately from the switching element and the control circuit section.